<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*justify-content属性
             flex-start：从左到右排列
             flex-end：从右到左排列
             center：中间开始排列
             space-between：平分
             space-around：平分，且两边占1/2
        */

        .flex-container {
            display: flex;
            display: -webkit-flex;
            width: 500px;
            background-color: darkcyan;
            justify-content: center;
            flex-direction: column;
        }

        .flex-item {
            width: 130px;
            height: 125px;
            margin: auto;
            margin-top: 10px  ;
            margin-bottom: 10px;
            background-color: yellowgreen;
        }

    </style>

<body>
<div class="flex-container">
    <div class="flex-item one">盒子1</div>
    <div class="flex-item tow">盒子2</div>
    <div class="flex-item three">盒子3</div>
</div>
</body>
</html>